1. Technical field
The present invention relates to a safety syringe, particularly to an auto-disable safety syringe of needle-protective functionality.
2. Background of the Art
At present, more and more diseases are contaminated through blood, bodily fluid, etc. One of main channels that cause disease to spread is using the same syringe for multiple times and inappropriately handling the needle of a syringe after it is used. However, commonly used disposable syringes may occasionally prick medical staffs after injection or hurt the workers processing medical waste later, thereby existing considerable latent safety problems. Although there have been many domestic or international patents in relation to disposable safety syringes, most of the syringes may not be widely adopted due to complicated configuration, high cost for manufacturing, inconvenience for use and functional inadequacy.
The patent of invention of filing No. 94101555.6 disclosed a disposable safety syringe, including a protective casing, which is moveably sleeved on the outside of a syringe barrel to make itself be able to move from an inactivated contracted position to a safety position in the front. Where it is at the inactivated contracted position, a needle protrudes from the protective casing, which has a fixation device to automatically retain the protective casing at the safety position in the front so that the protective casing cannot contract with respect to the syringe barrel. Such an invention can protect the needle, yet it has the following problems:
First, the overall configuration of the invention is complicated; thereby making its dies possess complex structures that shorten the service life of the dies. As a result, the investment on manufacture and cost goes up.
The second, the invention comprises many parts, which raise the difficulty of assembly process as well as production cost.
The third, the invention only carries out a protection for the needle. Yet no auto-latching and auto-disable functions regarding to the whole syringe are implemented. Therefore, some other parts (e.g. plunger) that might be taken off to reuse are still latent safety problems to patients.
The fourth, the invention reserves a defined space at the front end of the syringe, thereby bringing a considerable inconvenience for some applications of the syringe, e.g. blood withdrawal.